(a) Technical Field
The present disclosure generally relates to an exhaust gas recirculation (EGR) system for an engine. In particular, an EGR system having a short path is disclosed that evenly distributes exhaust gas across the cylinders of an engine.
(b) Background Art
One byproduct of internal combustion within an engine is the formation of nitrogen oxide (NOx) gasses. These types of gasses are formed when nitrogen (N2) combines with oxygen (O2) under the high temperatures associated with the combustion process, thereby forming NOx gasses such as nitric oxide (NO) and nitrogen dioxide (NO2). These gasses can have a number of adverse environmental effects when released into the atmosphere. For example, acid rain, smog, ozone layer depletion, and other adverse environmental effects have been attributed to the release of NOx gasses into the atmosphere.
To reduce the emission of NOx gasses by a combustion engine, EGR systems have been developed that recirculate exhaust gasses back into the intake of an engine. The exhaust gasses act as a “dilutant” in the combustion process, resulting in the reduction of pumping losses due to thermal dethrottling. NOx emissions are reduced since the recirculated gasses can also lower end-of-compression temperatures, thereby lowering combustion temperatures that can lead to the formation of more NOx gasses. Many EGR systems facilitate this lowering of temperatures by including EGR coolers that cools down the exhaust gasses before introducing the gasses back into the intake of an engine. Typically, these coolers operate by using the coolant of the engine to divert heat from the exhaust gasses.
While modern EGR systems are somewhat effective at reducing the emission of NOx gasses, this does not come without a price. First, engine efficiency is negatively impacted by virtue of the gas recirculation in an EGR system. Also, modern EGR systems typically add to the bulk, size, and complexity of an engine, which must accommodate the relatively long recirculation paths used by modern EGR systems. In particular, longer EGR paths can lower the response time of the EGR system, affect the response of the engine, etc.
In order to solve the problems in the related art, there is a demand for the development of EGR systems that exhibit better performance, improved fuel efficiency, and are smaller than conventional EGR systems.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.